A GlaxoSmithKline research and development facility. Image Credit: Bloomberg

London: A COVID-19 vaccine from GlaxoSmithKline Plc and Canada's Medicago Inc. demonstrated 71 per cent efficacy against multiple variants of the disease in a positive outcome for the pandemic latecomers.

The companies also found the plant-based vaccine showed 75 per cent efficacy against the highly-infectious delta variant and nearly 89 per cent efficacy against the gamma variant first identified in Brazil, according to the advanced-stage trial results published Tuesday. No vaccinated participants developed severe disease and no serious side effects were reported in the study on about 24,000 people.

The Omicron variant wasn't circulating at the time of the trial, but the company is planning to test the shot against the strain. The drugmakers are seeking authorization from regulators in Canada imminently and have started the filing process with the US Food and Drug Administration and the UK medicines regulator.

Glaxo and Medicago are among a second wave of vaccines coming into play after companies such as Pfizer Inc. and AstraZeneca Plc moved more quickly and had their vaccines authorized a year ago. Despite being the world's largest vaccine maker pre-pandemic, Glaxo doesn't have a Covid shot on the market yet.

While many high-income countries are now advanced in their vaccine programs, multiple shots are needed to vaccinate the global population and governments are considering which booster shots to offer.

The partners have a deal with the Canadian government to supply up to 76 million doses of the vaccine and are in talks with other countries about potential agreements, according to Medicago President and Chief Executive Officer Takashi Nagao.

Unique Data

"Not many manufacturers have been able to do the study at this kind of juncture when there is no original ancestral strain circulating any more, so that's the uniqueness of our data," Nagao said in an interview. "I like to consider us as to be one of the major league and within the major league there's a different technology platform" that we're offering.

The shot was given on a 1:1 vaccine-placebo ratio in the trial. There were 39 COVID cases in the vaccinated group and 118 in the unvaccinated arm. The shot was tested in a diverse group of people both in terms of age and ethnicity with good results across the board, but more analysis is needed, Nagao said.

If approved, the vaccine will be the first plant-derived shot for human use in the world. Glaxo is providing its adjuvant technology - substances that can enhance the response to vaccines - for the shot. The company is also planning booster studies and pediatric trials for the vaccine.

Given the stage of the crisis, the companies are pursuing a full rather than emergency license in most countries, including the UK. In the US, Medicago is in discussions with the regulator about whether it can seek a faster, emergency authorisation still, Nagao said.

Plant-based medicines can be produced quickly and at scale, making them a good technology for crises. The Glaxo-Medicago vaccine can be stored at refrigerator temperature making it easier to transport and use in lower-income countries than messenger RNA vaccines.

The vaccine was given to trial participants in two doses three weeks apart. The full trial results will be peer-reviewed and published as soon as possible, the companies said.